Radio frequency (RF) receivers are used in a wide variety of applications such as television, cellular telephones, pagers, global positioning system (GPS) receivers, cable modems, cordless phones, radios and other devices that receive radio frequency (RF) signals. RF receivers typically require frequency translation or mixing. For example, with respect to FM audio broadcasts, FM radio receivers may translate broadcast channels in the FM frequency band to an intermediate frequency, digitize the received signals, and then digitally process the digital signals to reproduce audio content for tuned channels. Within the United States, FM radios will typically translate FM audio signals, which are broadcast in 200 KHz channels in the frequency band from 88 MHz to 108 MHz, to an intermediate frequency of 10.7 MHz. FM demodulators and stereo decoders can then convert this 10.7 MHz IF signal to demodulated left and right audio signal that can be sent to stereo speakers. Although other countries will have different frequency bands and channel spacing, the reception of audio broadcast signals, such as FM audio broadcasts, is similarly accomplished using RF receivers.
Within the United States, high definition (HD) audio broadcasts are currently being provided by certain broadcasters. Protocols for HD radio in the United States were developed by iBiquity Digital Corporation. Unlike traditional analog FM broadcasts, HD radio broadcasts include digital radio broadcasts. The HD spectrums are described, for example, in the article Peyla, Paul J., “THE STRUCTURE AND GENERATION OF ROBUST WAVEFORMS FOR FM IN-BAND ON-CHANNEL DIGITAL BROADCASTING,” iBiquity Digital Corporation (2004), which is hereby incorporated by reference in its entirety. As described in this article with respect to the Hybrid Waveform, HD radio digital FM broadcasts can be implemented as sideband frequencies related to a primary analog FM broadcast channel. It is noted that this article contemplates that future generations of HD radio broadcasts will use more and more of the channel and sideband frequencies for digital content (e.g., Extended Hybrid Waveform, All Digital Waveform). In addition to the article above, the transmission and reception of HD radio broadcasts are further describe in U.S. Pat. Nos. 6,982,948, 6,430,227 and U.S. Published Patent Application No. 2005/0105657, each of which is hereby incorporated by reference in its entirety.